Photo by How Foo Yeen/Getty Images(NEW YORK) -- A massive search and rescue operation is underway in Southeast Asia for the Malaysia Airlines flight with 239 people on board lost contact with air traffic controllers.

The airline said there are 227 passengers, including two adult Americans and an infant, on board the Boeing 777-200 aircraft.

Flight MH370 departed Kuala Lumpur at 12:55 a.m. local time Saturday, and was scheduled to land in Beijing at 6:30 a.m., the airline said. It went missing two hours into the flight and disappeared off the radar.

Malaysia Airlines CEO Ahmad Jauhari Yahya said there was no indication that the pilots sent a distress signal. The fact that there was apparently no call for help suggests that whatever happened to the flight occurred quickly.

The New York Times reported on Saturday that a Vietnamese government official said a Vietnamese navy plane had spotted a large oil slick in the area where the plane was last known to be located. However, there was no confirmation that the slicks were related to the missing plane.

China has dispatched two maritime rescue ships and the Philippines deployed three air force planes and three navy patrol ships to help. The U.S. Navy's USS Pinckney is also on its way to help the search effort, the 7th Fleet announced on Twitter this morning.

A spokesman for Malaysia Airlines said Friday that the passengers included two adult Americans and a baby as well as travelers from Canada, Britain, Australia, France, India, the Netherlands, Russia and several other countries.

"We extend our deepest condolences to the loved ones of those on board Malaysia Airlines Flight MH370. At this time, we can confirm that three U.S. citizens were on board. Officials from the U.S. Embassies in Kuala Lumpur and Beijing are in contact with the individuals' families," State Department spokeswoman Jen Psaki said in a statement. "Out of respect for them, we are not providing additional information at this time. The Embassies are working to assess whether additional U.S. citizens may have been on board the flight."

The plane's route would take the aircraft from Malaysia across to Vietnam and China. Vietnam said on its official website that its air traffic controllers lost contact with the plane "in Ca Mau province airspace before it had entered contact with Ho Chi Minh City air traffic control." Ca Mau is near the southern tip of Vietnam.

The plane was meant to transfer to Ho Chi Minh City air traffic control at 1722 GMT but never appeared, the statement said, citing a senior Ministry of Defense official.

Malaysia's defense minister told a news conference, "We are trying to do everything in our power to [determine] where the plane is."

Malaysia Airlines said the captain of the airliner, Zaharie Ahmad Shah, was an experienced 53-year-old pilot who had 18,365 hours of flying since joining the airline in 1981. The first officer on the flight was identified as Fariq Hamid, 27, and had about 2,800 flight hours since 2007.

For hours, the flight information board at the airport in Beijing indicated the flight was delayed.

An airport official wrote on a white board near the arrivals customer service desk that families of the missing passengers should go to the Lido Hotel. The notice was put up about four hours after the plane was overdue.

"Friends and families should go to the Lido Hotel for more information," Eric Yangchao, customer service representative for Beijing International Airport, told ABC News. Family members took a shuttle bus to the hotel.

In a statement on Twitter, Boeing said it was watching the situation closely. The Malaysian aircraft, a Boeing 777-200, is 11 years and 10 months old. The 777 model had not had a fatal crash in its 20 year history until the Asiana crash in San Francisco in July 2013.